One of the methods used by an installer or other technician (e.g., an electrician) to locate a reference point on a first side of a structure (e.g., a wall, floor, ceiling, etc.) from a second side of the structure is to guess where the reference point might be on the first side of the structure and then drill a small test hole through the structure from the second side at the presumed location. With the test hole completed, the installer may move back to the first side of the structure and observe where the test hole came through the wall.
If the small hole came through the wall on the first side of the structure at or sufficiently proximate the reference point, the reference point was found and no further small holes may be required. However, if the small hole came through the wall on the first side of the structure undesirably or substantially far away from the reference point, the installer may move back to the second side of the structure, make another guess where the reference point might be on the first side (probably using the first small hole as a guide), and drill another test hole from the second side at the new location. Eventually, by repeating the above process a sufficient number of times, one of the subsequently drilled test holes will come through and open up on the first side of the structure at or sufficiently proximate the reference point on the first side. With the reference point now found, the installer is free to continue on with his work (e.g., fishing electrical wire to a new outlet being installed).